Provided are methods for processing semiconductor substrates or, more specifically, etching silicon containing antireflective coatings (SiARCs) from the substrates while preserving silicon oxides layers disposed on the same substrates. An etching solution including sulfuric acid and hydrofluoric acid may be used for these purposes. In some embodiments, the weight ratio of sulfuric acid to hydrofluoric acid in the etching solution is between about 15:1 and 100:1 (e.g., about 60:1). The temperature of the etching solution may be between about 30° C. and 50° C. (e.g., about 40° C., during etching). It has been found that such processing conditions provide a SiARC etching rate of at least about 50 nanometers per minute and selectivity of SiARC over silicon oxide of greater than about 10:1 or even greater than about 50:1. The same etching solution may be also used to remove photoresist, organic dielectric, and titanium nitride.